Robotic swing arms are widely used throughout the world to palletize a wide variety of packaged goods. Swing arm robots suitable for such use are available from a number of suppliers including specifically, but not exclusively, Kuka Robotics Corp of Augsburg, Germany; Fuji Robotics of Redmond, Wash., Fanuc Robotics of Rochester Hills, Mich., and Motoman Robotics Division of Yaskawa America, Inc. of West Carrollton, Ohio.
To achieve proper palletization of packages, the movement of swing arm robots is controlled by a protocol that includes x-y-z dimensional values based primarily upon the three-dimensional relationship between the fixed-position base of the swing arm robot, a fixed-position pick-up location for packages to be palletized, and a fixed-position pre-established drop-off location for each package onto the pallet.
In order to prevent the packages and/or their contents from being damaged during palletization, and also prevent the packages from bouncing or sliding out of position on the stack, swing arm robots are typically programmed and controlled so that they drop each package a minimal distance (e.g., an inch or so) onto the pallet or the immediately underlying layer of palletized packages. To achieve this, the drop height or z-dimension of the robotic swing arm is adjusted based upon the height of the current layer of packages being placed on the pallet. This is typically achieved by manually measuring one of the packages being palletized prior to initiating the palletization process, and inputting this value into the control system for the swing arm robot.
Despite such efforts, the palletization of fluid filled flexible packages (e.g., 50 lb bags of dog food or 20 lb bags of powdered milk) remain susceptible to package misalignment and loss of stack integrity due to shifting, sliding and bouncing of the packages as they are dropped onto the stack.
Accordingly, a need exist for a system and a method of automatically palletizing fluid filled flexible packages that minimizes misalignment of the stacked packages during palletization and thereby reduces the toppling, collapse or other structural failure of a palletized stack of the packages.